The flow rate regulation valve disclosed by, for example, Japanese Unexamined Patent Publication No. 11-230407 is currently used in various fields. This flow rate regulation valve includes a housing, in which a valve hole is formed, a needle valve that is adapted to move relative to the valve seat in the housing, a flow rate adjust knob mounted at the proximal end of the needle valve extending from the housing, a seal nut for adjusting the sealed state between the housing and the needle valve, and a panel nut for fixing the housing to a panel, wherein by rotating the flow rate adjust knob, the needle valve is moved relative to the valve seat thereby regulating the flow rate of fluid flowing through the valve hole.
This flow rate regulation valve, if used as a component part of a semiconductor manufacturing device, is mounted on the operation panel of the semiconductor manufacturing device or the housing of the semiconductor manufacturing device. FIGS. 4a to 4c are diagrams for explaining the manner in which an ordinary flow rate regulation valve is mounted on the panel. As shown in these drawings, if a flow rate regulation valve 100 is mounted on a panel 700, a flow rate adjust knob 400, a seal nut 900 and a panel nut 300 are removed in that order (FIG. 4a), and an extension 210 of the housing 110 from the proximal end of the needle valve 600 is inserted into a hole 750 formed in advance in the panel 700 (FIG. 4b). The panel nut 300 is them mounted on the extension 210, the flow rate regulation valve 100 is fixed, and the seal nut 900 and the flow rate adjust knob 400 are mounted again to make the flow rate regulation valve available for use (FIG. 4c).
After the flow rate regulation valve 100 is mounted on the panel 700, however, the flow rate adjust knob 400 is left exposed. Therefore, a user may accidentally touch the knob 400 of the flow rate regulation valve 100 causing the preset flow rate regulation valve 100 to change.
In the case where the knob 400 of the flow rate regulation valve 100 is rotated accidentally, not only the flow rate changes, but also the needle valve 600 rotates, together with the knob 400, resulting in that particles may develop due to frictional wear between the needle valve 600 and the housing 100, and therefore may intrude into the fluid. Especially, in the case where the needle valve 600 comes in contact with the valve seat, the particles generated by the frictional wear between the needle valve 600 and the valve seat also intrude into the fluid.
Further, as described above with reference to FIGS. 4a to 4c, the user removes the seal nut 900 provisionally to mount the flow rate regulation valve on the panel 700. The seal nut 900 is a part for setting the sealed state of the flow rate regulation valve. Once the seal nut 900 is removed, another problem may occur in that the same sealed state of the flow rate regulation valve as when it was shipped cannot be maintained.
This invention has been achieved in view of this situation and the object of this invention is to provide a flow rate regulation valve capable of preventing the flow rate from being changed by accidental operation of a user or the like.